Apparatus for the spraying of pulverulent materials



Dec. 6, 1955 w. D. JONES ET AL 2,726,118

APPARATUS FOR THE SPRAYING OF PULVERULENT MATERIALS Filed June 22, 1951 3 ShGtS-ShGSt l II II Jitflnicr$ M1619; D m: Lm z ,.1955 w. D. JONES ETAL 2,726,118

APPARATUS FOR THE SPRAYING OF PULVERULENT MATERIALS Filed June 22, 1951 3 Sheets-Sheet 2 11123:- D vk? Jam Dec. 6, 1955 w. p. JONES ETAL APPARATUS FOR THE SPRAYING OF PULVERULENT MATERIALS 3 Sheets-Sheet 3 Filed June 22, 1951 Imam": iiam D (7 4 9 M wo$e Dickini'ormy GNU l l l lglll l III APPARATUS FOR THE SPRAYING OF PULVERULEN T MATERIALS William David Jones and Robert Dickinson, London, England, assignors to Schori Metallising Process Limited, London, England Application June 22, 1951, Serial No. 232,916

10 Claims. (Cl. 29928.6)

This invention relates to apparatus for spraying metal or other fusible material of the kind in which the material in pulverulent form is conveyed into the apparatus in a stream of gas and fused and sprayed at a nozzle.

Such apparatus incorporates valve controlled conduits for the conveyal of the powdered metal in a suitable medium, a combustible gas, oxygen and compressed air and an object of the invention is to provide an improved control of such conduitswhich avoids the necessity of adjustable means incorporated in the apparatus for controlling such conduits. v

A further object is to provide improved manually actuated means by which the conduits may be controlled in the desired sequence.

Another object is to provide an improved and simplified construction of nozzle or head whereby only a single coned joint is necessary in assembling the parts of the head.

A further feature is to provide an improved and simplified unit construction whereby the parts may readily be assembled or disconnected, for example, in changing from one combustible gas to another.

The invention consists in an apparatus for spraying metal or other fusible material of the kind described wherein the conduits for. the combustible gas, oxygen, or other combustion supporting gas, and compressed air are controlled by shut down valve means and wherein manually actuated means are provided whereby such valves are operated in the desired sequence.

The invention also consists in an apparatus as set forth in the preceding paragraph wherein the head comprises inner, intermediate and outer elements forming concentric passages for the spraying metal and conveying medium, the combustible gas mixture and compressed air, the intermediate element incorporating the only coned seating surface providing a joint formed by tightening the outer element.

The invention also consists in an apparatus as set forth in either of the preceding paragraphs, comprising a head and nozzle section, an intermediate gas mixing section and a valve section and a base section, said section comprising units which are secured together by fastening means such as stud bolts and by means of unions to which suitable gas conveying means are attachable.

In the accompanying drawings:

Figure 1 is a sectional elevation of the improved spraying apparatus according to the invention.

Figure 2 is a sectional plan on line 2-2 of Figure 1.

Figure 3 is a sectional elevation of a powder supply container. 7

Figure 4 is a view showing the connecting of the spraying apparatus and powder container with a control panel.

In carrying the invention into effect according to one convenient mode by way of example, the metal spraying apparatus comprises a head section '1, a gas mixing section 2, a valve section 3 and a base 4.

The head section 1 is provided with a nozzle 5, the

" nited States Patent axis of which is inclined to the main longitudinal axis of the apparatus. In the head three borings 6, 7, 8 are provided for conveying respectively, compressed air, combustible gas and oxygen mixture, and the pulverulent material in an air or combustible gas under pressure.

The boring 8 opens into an axial bore 8a which is axially aligned with a nozzle element 9 which is fluted at 9a surrounding the outlet. The nozzle 9 is secured in the head by its inner threaded end 9b.

Concentric with the spraying metal nozzle 9 is a gas nozzle 10 spaced from the nozzle 9 to provide an annular passage 11 for the combustible gas and oxygen mixture. The outer end of the gas nozzle 10 is tapered and is fluted at 10b. The passage 11 opens at its inner end into a recess 12 in the head to which the bore 7 is connected. The outer end of the recess 12 is coned to provide a seating for the coned end 10a of the nozzle 10. The annular passage 11 at its outer end communicates with the fiutings 9a.

Surrounding the nozzle 10 and concentric therewith is a cap 13 which is screwed into an internally threaded recess 14 in the head. The recess 14 is in communication with the bore 6 in the head.

The cap 13 has an inner conedsurface 13a conforming to the tapered flutings ldb on the nozzle 10 thus providing a converging outlet for the compressed air. On tightening the cap 13 the nozzle 19 is forced axially on to its coned seat. It will be noted that this is the only joint to be made in the head.

The head 1 is secured to the mixer section 2 by stud bolts 15 passing through a flange 16 on the adjacent end of mixer section 2.

Conduits 17 and 18 are formed in the section 2 which open into the bores 6 and 7 respectively of the head 1.

At the lower end of the conduit 18 a recess 19 is provided forming a gas mixing chamber. In this chamher a gas nipple 2% is mounted by screw thread means, such nipple having an oxygen passage 21 with surround ing combustible gas ports 21a calibrated to suit the particular combustible gas to be employed. When the gas is to be changed the nipple 20 may be readily changed by separating the section 2 from the lower valve section 3, such sections being secured together by stud bolts 22.

The mixing section 2 has a lateral enlargement 23 which is hollowed out to form a seating for a moulded rubber valve member 24. A cap 25 which is also hollowed out to receive the valve member holds the member in position. At the upper end a tubular member 26 extends into the rubber valve. The member 26 extends through an aperture 27a in a lug 27 in section 2 and is seated on the head 1 in alignment with bore 8 by a screwed sleeve 28 engaging screw threads in the aperture 27a.

At its lower end the rubber valve 24 receives a nozzle 29 which is designed to produce a small diameter parallel stream of the spraying material and its conveying medium. A spring biassed stirrup 30 surrounds the rubber valve 24 and normally closes the valve.

By controlling the diameter of the stream passing through the valve 24 by the nozzle 29 the stream does not contact with the valve so that the wear of the valve is negligible. Replacement of the valve, however, is readily effected by removing the cap 25 and unscrewing a tube 31 upon which the nozzle 29 is mounted.

In the valve section 3 valve controlled passageways are provided for delivering compressed air to the conduit 17 in mixing section 2 and combustible gas and oxygen to the mixing chamber 9.

These valves are of a shut down'type and are of similar construction and therefore only that controlling the compressed air will be particularly described. The compressed air passage comprises two parts 32 one leading to a valve chamber 33 and the other'34 delivering from such chamber to conduit 17. The valve chamber 33 is closed by a screwed cap 35. The compressed air valve 36 is held on its seat 37 by spring 38 and is mounted'upon a valve stem 39 extending through a rubber packing 40 and screwed gland 41. The stem 39 carries an adjustable domed nut 42 having a lock nut whereby the domed nut is locked in position so that when the hand grip is moved to its locked position the valve 36 will be in fully open position.

The valve 43 controls the flow of oxygen from the passage 44 and chamber 45 to passage 46 which leads to the mixing chamber 9 in the mixing section 2. The valve 43 is mounted on stem 47 having an adjustable domed nut 43. From the chamber 45 a passage 49 leads to a bore 50 which is connected to passage 46 by a by-pass 51. The by-pass 51 provides a supply of oxygen for a pilot flame when the valve 43 is closed. The amount of the bypassed oxygen may be adjusted by a control screw 52.

A similar set of passages with valve 53 leading to the mixing chamber 9 is provided for a supply of fuel gas together with a controlled by-pass for a supply for the pilot flame, such lying in a plane parallel to the plane containing the oxygen valve 43 and its associated passages. The fuel gas valve 53 is provided with a stem 54 and adjustable domed nut 55.

The base unit or plate 4 upon which the hand grip 56 is pivotally mounted is secured to the section 3 by the unions 57 and 58 for compressed air and oxygen and a similar union for the fuel gas. Removably mounted on the base 4 is the tube 31 which has a union fitting 31a.

The hand grip 56 controls the opening of the valves 36, 43 and 53 for which purpose it is provided with a surface 57a for engaging the nut 4-2 on valve stem 39, and a surface 58 for engaging the nuts 48 and 55 on valve stems 47 and 54. The hand grip is also provided with a surface 59 for engaging the adjustable domed nuts 60 on the two arms of the stirrup 30. On actuation of the hand grip the valves will be moved to the fully opened position. It will be appreciated that no adjustment means for varying the opening of the valves is provided, they being either open or shut.

The disposition of the valves relatively to the hand grip is such that they are opened in the sequence combustible gas and oxygen, compressed air and spraying powder suspended in air or combustible gas.

The hand grip 56 is provided with a spring biassed pivoted catch 61 slotted to engage a pin 62 so that the hand grip will be locked in the valves open position. Pressure on the catch when in operative position will release the hand grip.

The powdered material is supplied from a container 63 by gravity feed through a nozzle 64 with which an adjustable feed control spindle 65 co-operates. The nozzle 64 projects into a chamber 66 having small inclined holes 67 which open into an annular chamber 68 to which the powder conveying gas is supplied through nozzle 69. Conveying gas entering the chamber 66 through the holes 67 entrains the powder entering the chamber 66 and passes therefrom by the outlet 70 and thence to the spraying apparatus.

An equalising pipe 71 connects the chamber 66 with the space above the powder in the container to ensure a steady flow of powder through nozzle 64. A vibrating device 72 of any known kind is mounted on the powder container.

As above pointed out no means for adjusting the opening of the valves is provided on the spraying apparatus but the necessary adjustment of the quantities of the gases is arranged by a control panel 72 having unions '73, 74, 75, which are connected respectively to the unions 57, 58, and a union for fuel gas respectively, by flexible hose 76, 77, 7 3.

A further union 79 on the panel for the conveying gas is connected by hose 80 to the inlet nozzle 69 on the powder-container.

The union 31a on the spraying apparatus is connected by a hose to the outlet 70 of the chamber 66 of the pow der supply container 63.

The unions 73 and 79 are connected to suitable control valves (not shown) of known form mounted in the panel and such valves are connected to supply unions 82 and 83 and these valves "are adjustable as required by hand controls 84, 85 to determine the rates of flow of conveying gas and air.

The oxygen and fuel gas unions are connected by pipes (not shown) to supply unions 86, 87 and these gas unions are controlled at the source of supply to determine the rates of flow.

The vibrator 72 may be operated by compressed air conveyed by hose 88 from an adjustable orifice union 89 on the panel and connected to the compressed air supply.

The combustible mixture may consist of oxygen or air and a fuel gas such as coal gas, acetylene propane or butane.

The gas conveying the powdered material is preferably a combustible gas 'such as coal gas as this will provide additional 'heat but air may be used.

The apparatus may be used for spraying any material which melts or becomes plastic at the temperature of the flame, for example, metals such as zinc, lead, tin, aluminium, copper and steel or non-metallic materials which do not decompose within their melting range such as sulphur, shellac, polyethylene, cellulose acetate butyrate, waxes and Thiokol.

In the improved spraying apparatus there are no high speed moving parts subject to wear, and by the absence of variable control valves the apparatus may be used by unskilled labour, the correct setting for any particular powder being all controlled at the control panel.

By means of the control panel the correct spraying pressures may be obtained to give optimum conditions and the rate of fiowof the powder may be varied from maximum downwardly without shutting off the spraying apparatus.

By the incorporation of a pilot flame for non-spraying periods the overall gas consumption is reduced to a minimum.

We claim:

1. An apparatus for spraying powdered metal or other powdered fusible material, comprising in combination a head, a spray nozzle on the head, a passage in the head for supplying to the nozzle the metal or other powder suspended in gas under pressure, a non-adjustable valve in said passage normally biassed to closed position, conduits in the head for supplying to the nozzle combustible gas under pressure, combustion supporting gas under pressure, and air under pressure, a non-adjustable shutoff valve in each conduit and normally biassed to closed position, a member manually operable for opening all said valves and which positively ac'tuates the shut-off valves to move'and hold them in their fully open positions, and valves adjustable in pipe connections leading to the head for independently determining the rates of supply of said combustible gas under pressure, combustion supporting gas under pressure and air under pressure to said conduits.

2. An apparatusfor spraying powdered metal or other powdered fusible material as claimed in claim 1 wherein when said member is operated the combustible gas and combustion supporting gas shut-ofi valves are opened prior to the opening of the shut-off valve for compressed air and the valve for the gas having the powder suspended therein.

3. An apparatus as claimed in claim 1 wherein the spray nozzle comprises inner, intermediate and outer tubular elements providing an inner passage for the suspension, and concentric passages respectively for a mixture of combustible gas with combustion supporting gas, and

compressed air, the intermediate element incorporating a conical surface at its inner end which seats on a similar surface in the head and which forms the only joint in the head upon tightening the outer element on the head.

4. An apparatus as claimed in claim 3, wherein the head comprises a spray nozzle section, a section having a chamber in which combustible gas and combustion supporting gas are mixed, a shut-off valve section and a base section each of which sections is a unit, the units being secured together by stud bolts and pipe unions are provided which are adapted to have flexible pipes attached thereto respectively for supply to the head compressed air, combustible gas, combustion supporting gas and suspension of the powder in gas under pressure.

5. An apparatus as claimed in claim 4, wherein a mixing chamber for the combustible gas and combustion supporting gas is located in the gas mixing section adjacent the junction between said section and the shut-off valve section, said chamber accommodating a gas nipple which may be inserted according to the combustible fuel gas being used, by a separation of said sections.

6. An apparatus as claimed in claim 1, wherein the manually operable member comprises a hand grip pivotally mounted on the base section and having surfaces adapted to engage stems of the shut-01f valves which move on axes transverse to the general direction of flow through the conduits and the valve in the passage for the suspension comprises a moulded rubber sleeve normally contracted to closed position by a spring biassed stirrup piece and which expands to fully open position on actuation of the stirrup against the action of its spring by the hand 7. An apparatus as claimed in claim 6, wherein the suspension is delivered to the rubber sleeved by a nozzle which produces a relatively small diameter parallel jet which does not contact with said sleeve.

8. An apparatus as claimed in claim 7, wherein the rubber sleeve is mounted in a seating by a removable cap piece whereby the sleeve may readily be changed.

9. An apparatus as claimed in claim 1, wherein the combustible gas and oxygen shut-off valves are located in chambers from which by-passes open into the respective conduits whereby a combustible mixture for a pilot flame is available at the nozzle when said shut-off and suspension valves are closed.

10. A plant for spraying powered metal or other fusible material comprising a spraying apparatus as claimed in claim 3 wherein a control panel is provided having unions for connection by flexible hose to the unions on the spraying apparatus, said panel incorporating adjustable valves for determining the rate of How of compressed air and powder conveying gas.

References Cited in the file of this patent UNITED STATES PATENTS 1,617,166 Schoop Feb. 8, 1927 1,998,217 Benoit Apr. 16, 1935 2,072,845 Benoit Mar. 9, 1937 2,091,021 Stevens Aug. 24, 1937 2,108,998 Schori Feb. 22, 1938 2,125,764 Benoit Aug. 2, 1938 2,150,949 Stevens Mar. 21, 1939 2,549,736 Wiese Apr. 17, 1951 

